Elevator Backup System

ABSTRACT

A method of controlling an elevator system comprises transferring power to an elevator car from a primary power supply to a backup power supply without interruption of power if the primary power supply fails or is disrupted. Following transfer of power to the elevator car from the primary power supply to the backup power supply either pending operations of the elevator car are completed or the elevator car is moved to a predetermined floor based on pending operations of the elevator car. The backup power supply can be attached to the elevator car.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/006,182, filed Dec. 28, 2007, entitled “Prismatic Battery UtilizingContinuous Bus Bar Collectors Between Electrodes”, and U.S. ProvisionalApplication No. 61/100,318, filed Sep. 26, 2008, entitled “RechargeableZnMn Flat Plate Electrode Cell”, the disclosures of which are herebyincorporated by reference in their entireties.

BACKGROUND

Elevator systems exist that, in the event of a power system failure,move an elevator car or allow the elevator car to be moved to the nextlower floor. A backup power supply system often moves the elevator carto the next lower floor very slowly, or gravity is used to allow theelevator car to move down to the next floor. When the elevator cararrives at the next lower floor the elevator car doors are then openedusing the backup power supply system, or the doors may be pried open.

A problem with conventional battery backup systems is that the batteryloses power overtime and may not have enough power to move the elevatorcar to a floor and open the door to allow the passengers to get off ofthe elevator car safely. As such, the battery must be routinely checkedto ensure sufficient battery power, and replaced in the event there isinsufficient power. Since batteries may discharge at different ratesdepending on factors including heat, age, and usage, determining thefrequency of battery checks is difficult.

Another problem with conventional elevator backup systems is that due tothe size requirements, and resultant weight of the battery or generatorwhich is to provide the necessary power to backup the elevator system,the backup battery or generator must be kept separate from the elevator,and in particular at the bottom of the elevator shaft, for example, inthe basement of the building housing the elevator. However, severestorms, for example, hurricanes, that can cause elevator power systemfailures, may be accompanied by heavy rain that may result in buildingflooding, which would render the battery backup or generator stored inthe basement of the building unusable. Further, a flooded areacontaining a submerged or partially submerged backup battery orgenerator may result in dangerous conditions, as chemicals within thebattery or generator may leach or leak out into the floodwater.

What is needed are new elevator backup systems, for example, in the formof a rechargeable battery, that avoid the problems outlined above. Anelevator backup system in the form of a rechargeable battery that avoidsthe problems outlined above must overcome problems of conventionalrechargeable batteries, which move current from an active material to anexternal terminal through effectively parallel paths. In general,current is collected from one side of an electrode, often through asingle tab. Thus, a current restriction is created at the tab connectionwhere the current paths merge. The created current restriction createsresistance that increases with the size of the electrode. Thus, thereexists a minimum limitation on the size of batteries for a givenperformance (power, efficiency, etc.).

While ZnMn chemistries for batteries are low cost and lightweight, areenvironmentally benign, and have a very long charge retention,currently, the only batteries (rechargeable or non-rechargeable)commercially available with ZnMn chemistries are round bobbin cells.Round bobbin cells have a positive electrode that is stamped or pressedinto a cylindrical hollow pellet and seated into a can, and the negativeelectrode is a gel that is filled into the center void of the positiveelectrode.

The high internal resistance of low capacity round bobbin cells limitsthe currents (i.e., power) that they can deliver. In contrast, flatplate (electrode) cells can be scaled up to large sizes providing highcurrents and storage capacities.

CA 2 389 907 A1 relates to a method of producing flat plate electrodesin a small format that exhibit high current densities, higherutilization of the active materials, and better rechargeability. Themethod of forming the electrodes requires the active materials, binders,thickening agents, additives, and an alkaline electrolyte to form apaste that is applied to a current collector. CA 2 389 907 A1 providesis a flat plate rechargeable alkaline manganese dioxide-zinc cell.

An elevator backup system in the form of a rechargeable battery thatavoids the problems outlined above should exhibit improvements in, forexample, current density, memory effect (i.e., capacity fade), shelflife, charge retention (e.g., at higher operation temperatures), andvoltage level of discharge curve over known round bobbin and flat platecells.

SUMMARY

Provided is a method of controlling an elevator system. The methodcomprises transferring power to an elevator car from a primary powersupply to a backup power supply without interruption of power if theprimary power supply fails or is disrupted. Following transfer of powerto the elevator car from the primary power supply to the backup powersupply either pending operations of the elevator car are completed orthe elevator car is moved to a predetermined floor based on pendingoperations of the elevator car.

Also provided is an elevator system comprising an elevator car; aprimary power supply; and a backup power supply attached to the elevatorcar.

Further provided is a prismatic battery comprising an electrode stackcomprised of positive electrode plates, negative electrode plates, andseparator layers therebetween. The positive electrode plates comprisepositive electrode plate extensions that extend beyond a periphery ofthe electrode stack, and the positive electrode plates are arranged suchthat the positive electrode plate extensions are aligned with oneanother. The negative electrode plates comprise negative electrode plateextensions that extend beyond a periphery of the electrode stack, andthe negative electrode plates are arranged such that the negativeelectrode plate extensions are aligned with one another. The prismaticbattery further comprises positive current collectors formed by fusingthe positive electrode plate extensions and negative current collectorsformed by fusing the negative electrode plate extensions.

Additionally provided is a flat plate electrode cell comprising positiveelectrode plates each comprising manganese and compressed metal foam andnegative electrode plates each comprising zinc and compressed metalfoam.

Accordingly, moreover provided is a rechargeable prismatic batterycomprising an electrode stack comprised of positive electrode plates andnegative electrode plates. The positive electrode plates each comprisemanganese, compressed metal foam, and positive electrode plateextensions that extend beyond a periphery of the electrode stack, andthe positive electrode plates are arranged such that the positiveelectrode plate extensions are aligned with one another. The negativeelectrode plates each comprise zinc, compressed metal foam, and negativeelectrode plate extensions that extend beyond a periphery of theelectrode stack, and the negative electrode plates are arranged suchthat the negative electrode plate extensions are aligned with oneanother. The prismatic battery further comprises positive currentcollectors formed by fusing the positive electrode plate extensions andnegative current collectors formed by fusing the negative electrodeplate extensions.

The rechargeable prismatic battery of the present disclosure providesimprovements in, for example, current density, memory effect (i.e.,capacity fade), shelf life, charge retention (e.g., at higher operationtemperatures), and voltage level of discharge curve over known roundbobbin and flat plate cells. In particular, the rechargeable flat plateelectrode cell of the present disclosure provides longer cycle life withreduced capacity fade as compared with known round bobbin and flat platecells.

The rechargeable prismatic battery of the present disclosure achievessuch benefits through unique electrode formation and electrodearrangement. In particular, both the positive and negative electrode ofthe rechargeable flat plate electrode cell of the present disclosure areformed from compressed metal foam, which provides both low resistanceand high rate performance to the electrodes and the cell. Additionally,the rechargeable prismatic battery of the present disclosure movescurrent from the active material to an external terminal throughmultiple directions in a manner that is efficient in cost, volume, andweight and current via extensions from electrode plates at multiple(e.g., two, three, four, five, six, seven, eight, etc.) locations alonga periphery of an electrode stack.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING

FIG. 1 depicts electrode plate extensions on multiple sides of electrodeplate stacks, as described herein.

FIG. 2 depicts the assembly of positive electrode plates and negativeelectrode plates.

FIG. 3 depicts effect of various tabs on rate or power capability of abattery.

FIG. 4 depicts conventional connection of electrode tabs to collectorsindividually.

FIG. 5 depicts fusing of electrode plate extensions into a continuousstrip or bus bar, as described herein.

FIG. 6 a depicts the space required in a battery for conventionalconnection of individual electrode tabs to collectors, while FIG. 6 bdepicts the space required in a battery for a continuous strip or busbar formed by fusing electrode plate extensions, as described herein.

FIG. 7 depicts nesting and overlapping of adjacent electrode plateextensions, as described herein.

FIG. 8 depicts the assembly of positive electrode plates and negativeelectrode plates, according to an embodiment.

FIG. 9 depicts the assembly of positive electrode plates and negativeelectrode plates, according to an embodiment.

FIG. 10 depicts the assembly of a series of electrode stacks, asdescribed herein.

FIG. 11 shows the improvements of a rechargeable flat plate electrodecell comprising compressed metal foam over commercially available ZnMnround bobbin consumer cells in terms of Cell Capacity Versus DischargeRate.

FIG. 12 shows the improvements of a rechargeable flat plate electrodecell comprising compressed metal foam over commercially available ZnMnround bobbin consumer cells in terms of Cell Capacity versusCycles/Life.

DETAILED DESCRIPTION

The present method of controlling an elevator system comprisestransferring power to an elevator car from a primary power supply to abackup power supply without interruption of power if the primary powersupply fails or is disrupted. Following transfer of power to theelevator car from the primary power supply to the backup power supplyeither pending operations of the elevator car are completed or theelevator car is moved to a predetermined floor based on pendingoperations of the elevator car.

As used herein, the phrase “pending operations” refers to floor stopsrequested by one or more elevator riders prior to primary power supplyfailing or being disrupted. Thus, completing pending operations wouldinclude moving the elevator car to a requested floor and opening one ormore elevator car doors. In contrast to elevator systems that, in theevent of a power system failure, move an elevator car or allow theelevator car to be moved to the next lower floor, passengers inelevators equipped with the elevator backup system of the presentdisclosure may not be aware of the power outage until the elevator caropens its doors at the requested floor stop, after which the elevatorsystem may shut down.

Alternatively, the elevator controller may be programmed such that inthe event the pending operations include one or more floor stop requeststhat may be undesirable in the condition of a power outage (e.g., abelow-ground level without emergency lighting), rather than completingthe pending operation(s), the elevator car may be moved to apredetermined floor (e.g., a ground floor level). The primary powersupply can comprise AC power, while the backup power supply can compriseDC power.

The present elevator system comprises an elevator car, a primary powersupply, and a backup power supply attached to the elevator car. Forexample, the backup power supply can be located on top of the elevatorcar. By attaching the backup power supply to the elevator car, problemsassociated with a battery backup or generator stored, for example, atthe bottom of the elevator shaft can be avoided. However, a backup powersupply attached to an elevator car must overcome size and resultantweight requirements of known backup systems. The primary power supplycan comprise AC power, while the backup power supply can comprise DCpower.

As the backup power supply is attached to the elevator car, theoperability of the elevator may be maintained, despite the primary poweroutage. Depending on the power and/or capacity of the backup powersupply attached to the elevator car, the elevator may be operated in itsregular course, or may be operated in a “power save” mode, for example,with reduced lighting. The elevator system can further comprise solarrecharging capabilities for the backup power supply.

In an embodiment, the backup power supply comprises a rechargeableprismatic battery comprising an electrode stack comprised of positiveelectrode plates and negative electrode plates. The positive electrodeplates each comprise manganese, compressed metal foam, and positiveelectrode plate extensions that extend beyond a periphery of theelectrode stack, and the positive electrode plates are arranged suchthat the positive electrode plate extensions are aligned with oneanother. The negative electrode plates each comprise zinc, compressedmetal foam, and negative electrode plate extensions that extend beyond aperiphery of the electrode stack, and the negative electrode plates arearranged such that the negative electrode plate extensions are alignedwith one another. The prismatic battery further comprises positivecurrent collectors formed by fusing the positive electrode plateextensions and negative current collectors formed by fusing the negativeelectrode plate extensions.

The rechargeable prismatic battery of the present disclosure reduces thematerial costs, weight, toxicity (regulated limitations), volume, andmaintenance of known batteries, while increasing charge retention andreliability. The rechargeable prismatic battery of the presentdisclosure comprises one or more anode plates comprising anode paste andone or more cathode plates comprising cathode paste. The anode andcathode pastes each comprises active material metal powders (e.g., zincand manganese, respectively) mixed with aqueous or organic binder tocreate a paste that can be consistently coated on one or both sides of asubstrate. The substrate holds the active material (i.e., the paste) andacts as a current collector. In an embodiment, the substrate is made ofa conductive material such as steel, Ni, or Cu, and may be plated withindium or Ni (i.e., a material that is non-active relative to MnO₂) forthe cathode and Cu (i.e., a non-active material relative to zinc) forthe anode. In an embodiment, the substrate comprises a porous conductivesubstrate such as, for example, perforated metal, metal foam, metalfelt, expanded metal, or carbon foam. More specifically, the substratecomprises nickel foam and/or copper plated nickel foam. Accordingly, theanode or cathode paste is coated on and throughout the foam mesh.

The coated substrate is dried and sized (i.e., compressed) to create ahighly conductive, dense, porous flat plate electrode. The flat plateelectrodes can be wrapped and sealed in a layer of barrier and separatormaterial to prevent short circuits and dendrite growth, or separatorlayers between the electrodes can be used. The (wrapped and sealed) flatplate electrodes are stacked in an alternating cathode and anode patternthat is repeated until a desired capacity of the cell is reached.Electrode plate extensions, as further described below, of the flatplate cathode electrodes are connected together and electrode plateextensions, as further described below, of the flat plate anodeelectrodes are connected together. In an embodiment, the rechargeableflat plate electrode cell of the present disclosure is bi-polar. Suchbipolar batteries use a substrate to hold the positive active materialson one side and negative active materials on the other and the substrateacts as a cell wall. The cell walls are sealed either peripherally ortangentially to hold internal pressure and electrolyte.

In metal foams, typically 75-95% of the volume consists of void spaces.As such, the use of metal foams allows for thicker electrode substrateswithout increasing the resistance of the electrode substrates. Targetcompression from sizing for this embodiment is between about 42% and45%, which gives desirable porosity, required for low resistance/highrate performance of the rechargeable flat plate electrode cell.

Without wishing to be bound by any theories, it is believed that thehigh density of compression reduces the resistance within the paste byreducing the distance between active particles in the active materialand reduces the resistance to the substrate by bringing the activeparticles closer to it. The high density reduces the volume so theenergy density is increased. The high density also reduces the voidvolume in the active material which reduces the amount of electrolyterequired to fill the electrode which in turn reduces the rate at whichdendrites are formed which protects the cell from shorting and increasescycle life. The density level is critical since over-compression willcause dry spots in the active material where electrolyte cannot get to.These dry spots are very high resistance which reduces performance andcan create gassing areas which cause cell failure.

Without sizing, desired energy density and high power capability are notachieved. The target coated sized thickness for the cathode is less thanabout 0.0300 inches. Coated sized thickness for the cathode greater thanabout 0.0300 inches results in rate capability (power) losses, whilecoated sized thickness for the cathode less than about 0.0200 inchesresults in energy density losses, due to excess inter electrode spacingand substrate relative to active material.

The anode paste comprises about 75-98 weight %, for example, about 83.1weight %, zinc active material; about 0.01-1.0 weight %, for example,about 0.27 weight %, polymeric binder; and about 0-20 weight %, forexample, about 16.6 weight %, solid zinc oxide. Exemplary zinc activematerials include lead-free zinc and zinc alloy, such as, for example,in metallic, powder, granular, particulate, fibrous, or flake form.

The cathode paste comprises about 70-90 weight % electrolytic manganesedioxide; about 2-15 weight %, for example, about 7.5 weight %, graphiteand/or carbon black; about 3-10 weight %, for example, about 6 weight %,polymeric binder; about 1-15 weight %, for example, about 5 weight %,barium compound; and about 0.01-10 weight %, for example, about 5 weight%, hydrogen recombination catalyst. Exemplary barium compounds includebarium oxide, barium hydroxide, and barium sulfate. Exemplary hydrogenrecombination catalysts include silver, silver oxides, and hydrogenabsorbing alloys. The cathode paste may further comprise indium.

Exemplary polymeric binders of either the cathode paste or anode pasteinclude carboxymethyl cellulose (CMC), polyacrylic acid, starch, starchderivatives, polyisobutylene, polytetrafluoroethylene, polyamide,polyethylene, and a metal stearate. The polymeric binder of either thecathode paste or anode paste can include conductive graphite, forexample, conductive graphite having an average particle size between 2and 6 microns.

The rechargeable prismatic battery of the present disclosure differsfrom currently commercially available rechargeable ZnMn batteries inthat the flat plate electrodes of the cell:

-   -   are flat;    -   have an internal carrier (substrate);    -   have a current collector attached to the internal carrier; and    -   have the anode's active material completely sealed in a barrier        to stop dendrite failures.

The rechargeable prismatic battery of the present disclosure furtherdiffers from currently commercially available batteries in that:

-   -   flat plate cathode electrodes are produced by use of aqueous or        organic binder and metal powder which is coated, dried and        sized, instead of a glycol gel that is injected into a barrier        wrapped pocket, which allows for the production of high volume        flat plate electrodes required for economical power backup        batteries;    -   flat plate anode electrodes are produced by use of an aqueous or        organic binder and metal powder which is coated, dried, and        sized, instead of mixing and then high pressure stamp forming        into a ridged pellet, which allows for the production of high        volume flat plate electrodes required for economical power        backup batteries;    -   multiple flat plate cathode electrodes and flat plate anode        electrodes can be connected in parallel then placed in a        container, filled with electrolyte, and then sealed, instead of        a cathode pellet wedged into a metal can, a barrier separator        inserted into the cathode pellet cavity, and then anode gel        injected into the cavity with a metal pin inserted into the        center of the gel, and closed using a seal ring and crimping,        which allows for the high capacity required for stationary power        backup batteries.

Advantages of the rechargeable prismatic battery of the presentdisclosure include:

-   -   reducing battery cost through lower material costs, lower        production costs, and using fewer components;    -   reducing battery weight through higher energy dense chemistry,        and using fewer components;    -   reducing battery volume through higher energy dense chemistry,        and using fewer components;    -   reducing environmental and regulated (storage, disposal,        shipping) issues by using environmentally friendly chemistry;    -   improving reliability by using batteries with higher capacities        and internal series collectors so fewer batteries/connections        are used;    -   reducing continuous energy losses by using a chemistry with        higher charge retention; and    -   reduces energy losses in the system by improving performance        (charge efficiency, rate capability) through battery design that        reduces losses from internal resistance in the battery.

The rechargeable prismatic battery of the present disclosure alsodiffers from currently commercially available rechargeable ZnMnbatteries in that current is drawn from the flat plate electrodes of thecell in multiple (e.g., opposite) directions, thus reducing:

-   -   magnetic signature during use;    -   resistance and increasing the rate capability of the cell,        allowing ZnMn chemistry to function at a much higher rate such        that it is practical for use as power backup;    -   voltage gradient across the flat plate electrode, which reduces        the irreversible reactions that take place on high rate        charge/discharge as well as at end of charge and end of        discharge, which increases the cycle life of the battery such        that it is practical for use as power backup.

The rechargeable prismatic battery of the present disclosure reduce thecorrelation between battery size and power/efficiency, so that batteriescan be made any size without a meaningful drop in performance, andreduce resistance in batteries, specifically reduce the delta (i.e., thedifference) between the highest and lowest resistance areas of batteryelectrodes. A high delta between resistance areas causes activematerials in areas of high and low resistance to be pushed intoovercharge or reversal on charge or discharge which causes degradationof the battery (e.g., gassing, high pressure, breakdown of theseparator/binder, loss of active material, competing side reactions,etc.).

In particular, FIG. 1 illustrates electrode plates in accordance withthe rechargeable prismatic battery of the present disclosure. Asillustrated in FIG. 1 a, both positive electrode plates and negativeelectrode plates used to form an electrode stack can have four sides.The positive electrode plates can have positive electrode plateextensions on opposing sides, while the negative electrode plates canhave negative electrode plate extensions on complementary opposingsides. While FIG. 1 illustrates the electrode plate extensions in a flatform, prior to assembly of the electrode stack, the electrode plateextensions can be bent, as illustrated in FIG. 2. While not shown inFIG. 2, in the electrode stack, the alternating positive and negativeelectrode plates are separated by separator layers, which insulate theelectrode plates from one another.

Thus, as used herein, the phrase “electrode plate extensions” refers tosegments of the individual electrode plates which extend beyond the areaof an electrode stack that includes layers of positive electrode plates,negative electrode plates, and separator layers therebetween. Again,during assembly of the electrode stack, the electrode plate extensionscan be bent in a form to be discussed further below. Similarly, as usedherein, the phrase “electrode extensions” refers to the cumulativepositive and/or negative electrode plate extensions of the electrodestack.

As illustrated in FIG. 1 b, both positive electrode plates and negativeelectrode plates used to form an electrode stack can have six sides. Thepositive electrode plates can have, for example, three positiveelectrode plate extensions on alternating sides, while the negativeelectrode plates can have, for example, three negative electrode plateextensions on complementary alternating sides. Thus, for an electrodestack whose periphery has a finite number of sides (i.e., not acylindrical electrode stack), the multiple locations along the peripheryof the electrode stack can correspond to the sides of the electrodestack. In particular, for an electrode stack whose periphery has an evennumber of sides, the positive or negative electrode extensions can bepresent on alternating sides of the electrode stack and/or half of thesides of the electrode stack. Alternatively, for a cylindrical electrodestack, the multiple locations along the periphery (i.e., circumference)of the electrode stack at which electrode extensions are present can bereferred to as “sides” of the electrode stack (see FIG. 1 c).

Restriction at conventional tabs is reduced by adding more and/or largertabs. With regard to the size of the tabs, as tab area increases, therate or power capability of the battery increases. Thus, FIG. 3illustrates that a welded collector of a wound battery (i.e., acollector providing multiple point of connection between an electrodeand a tab) could provide 10 times a “Base Rate Power” (i.e., the powerof a standard battery having a single tab attached to an electrode),while a tab that is coextensive with a side of an electrode couldprovide 15 times the “Base Rate Power”. In comparison, the electrodeextensions of the rechargeable prismatic battery of the presentdisclosure (see, for example, FIG. 1; not shown in FIG. 3) could provide20 times to 30 times the “Base Rate Power”.

As illustrated in FIG. 4 and FIG. 6 a, conventional connection ofindividual tabs to collectors can take up 5-30 volume % of mostbatteries and is the main resistance point, because the tabs extend fromindividual electrode plates in substantially the same plane as theelectrode plates and then must be gathered for connection to collectors.In contrast, as illustrated in FIG. 5 and FIG. 7, bent electrode plateextensions of the rechargeable prismatic battery of the presentdisclosure readily cooperate and nest with adjacent electrode plateextensions such that overlapping electrode plate extensions can bereadily fused together to form a continuous strip or bus bar so that asthe battery grows in size (e.g., capacity or number of electrode plates)the bus bar (i.e., current collector) automatically grows with it.Stated otherwise, electrode plates are connected via electrode plateextensions to form a continuous bus bar. The rechargeable prismaticbattery of the present disclosure thus eliminates the need forindividual tabs on electrode plates (which would either be coupledtogether for connection to a terminal or individually connected to acurrent collector) and fuses the individual electrode plates in acontinuous bus bar. Positive current collectors can then be connected toeach other and to a terminal, and negative current collectors can thenbe connected to each other and to a terminal. Thus, as illustrated inFIG. 6 b, the rechargeable prismatic battery of the present disclosureminimizes the amount of battery volume required for connection ofelectrode plates to terminals.

As the rechargeable prismatic battery of the present disclosureessentially replaces a conventional single tab with continuous bus barson multiple sides of an electrode stack, the rechargeable prismaticbattery of the present disclosure reduces the distance current has totravel through electrode plates. For example, with a conventional singletab, the longest distance that current would have to travel throughelectrode plates would be the length of the electrode plates. Incontrast, with the continuous bus bars on multiple sides of an electrodestack of the rechargeable prismatic battery of the present disclosure,the longest distance that current would have to travel through electrodeplates would be one half the length of the electrode plates (i.e.,assuming an electrode stack with four sides, two positive electrodeplate extensions on opposing sides, and two negative electrode plateextensions on complementary opposing sides; more sides on the electrodestack and correspondingly more electrode plate extensions would furtherreduce the distance that current would have to travel through electrodeplates). The cumulative effect on the battery is to reduce the totalresistance of the battery, which improves performance (e.g., rate) andreduces the delta between the high and low resistance areas on theelectrode while spreading them out so that degradation of batteryperformance is reduced. Thus, costs, weight, and volume are reducedwhile increasing performance.

In order to further reduce the distance current has to travel throughelectrode plates, one or more sections of the electrode plates can be“punched out”, with electrode plate extensions present in such punchedout sections of the electrode plates, as illustrated in FIG. 8. Thebenefit of including such “internal” electrode plate extensions (i.e.,reducing the distance current has to travel through electrode plates),should be weighed against the loss of electrode plate area, which resultfrom punching out the one or more sections from the electrode plates.

The spacing between electrode plates in conventional batteries ismaintained by axial pressure on the electrode plates and the resistanceto that pressure by the separator(s). The spacing between the electrodeplates is critical for chemical transfer and directly effectsperformance and efficiency. In an embodiment, the rechargeable prismaticbattery of the present disclosure locks the spacing between theelectrode plates as the continuous bus bar is formed. For example, thesubstrate or electrode plate extensions can be exposed the length of3.25 cell stacks and bent at an 85° angle, for both positive andnegative electrode plates. The length of 3.25 cell stacks insures thatat least 3 layers of metal (substrate or electrode plate extensions) areon the outside of the active cell (positive active material, separator,negative active material). As these layers are stacked (positiveelectrode, separator, negative electrode, separator, then repeated asmany times as defined for capacity of the cell) the exposed bent lengthof substrate will nest with the same electrode above it. The 85° angleis functional for good nesting when the electrode thicknesses are about0.030 inches and the substrates are 0.003 inches thick. If these twothicknesses change the ideal angle would change. The electrode stack iscompressed to the target spacing between the electrode plates, then thebent electrode plate extensions are fused into a continuous bus bar. Thebent electrode plate extensions can be fused into the continuous bus barby, for example, resistance welding or metalized spraying.

The length of the electrode plate extensions, and resultantly, theamount of overlap of nesting electrode plate extensions can depend onthe method used to fuse the bent electrode plate extensions into thecontinuous bus bar. For example, metalized spraying might fuse, forexample, two layers of electrode plate extensions. Thus, a length ofelectrode plate extensions that provides three overlapping layers ofelectrode plate extensions will allow for creation of a continuous busbar by fusing the top two layers, while the third layer can protect theelectrode stack from the metalized spraying during the fusing process.Resistance or Laser welding likewise could be used to fuse the outsidetwo layers while the third inside layer would act as a buffer protectingthe active material and separator from heat, sparks, or other debriswhich could cause damage (such as a short circuit) to the cell stack.

As the current collectors run along the side of the electrode stack, theseparator layers can comprise a wrapping of electrode plates to protectand insulate the edges of electrode plates from the current collectors.In an embodiment, electrode plates are wrapped with separator layermaterial such that only electrode plate extensions of the electrodeplates are exposed.

Further advantages of the rechargeable prismatic battery of the presentdisclosure include improved manufacturability. As all positive electrodeplates are interchangeable (i.e., positive electrode plate extensions donot differ between different positive electrode plates in an electrodestack) and all negative electrode plates are interchangeable (i.e.,negative electrode plate extensions do not differ between differentnegative electrode plates in an electrode stack), the method of assemblyof the rechargeable prismatic battery of the present disclosure simplyincludes stacking alternating layers of positive electrode plates andnegative electrode plates, with separator layers in between, whilearranging the positive electrode plates such that the bent positiveelectrode plate extensions are aligned with one another and arrangingthe negative electrode plates such that the bent negative electrodeplate extensions are aligned with one another. The shape of theelectrode plate extensions does not change following fusing to formcurrent collectors.

Additionally, by reducing the amount of battery volume required forconnection of electrode plates to terminals, the rechargeable prismaticbattery of the present disclosure increased the amount of volume of thebattery that is occupied by the electrode stack. Further, as theconnection of positive current collectors to each other and to aterminal and of negative current collectors to each other and to aterminal requires a minimal amount of space, the rechargeable prismaticbattery of the present disclosure allows for “flexible orientation”.That is, the terminals of the battery can be located proximate to anysurface of the electrode stack, as opposed to the need in conventionalbatteries for the terminals to located near the tabs of the electrodeplates. In an embodiment, the connected positive current collectorsand/or connected negative current collectors are insulated from theelectrode stack.

While FIGS. 2 and 8 illustrate assembly of an electrode stack such thatboth the positive and negative electrode extensions face the samedirection (i.e., electrode stack surface), in an embodiment, theelectrode plates can be assembled such that the positive electrodeextensions face a different (e.g., opposite) direction (i.e., electrodestack surface) than the negative electrode extensions, as illustrated inFIG. 9. An advantage of such an electrode stack construction isallowance of ease of coupling of electrode stacks in series.

For example, FIG. 10 illustrates how three such electrode stacks can beconnected in series, such that the positive electrode extensions/currentcollectors of a first electrode stack can be fused (e.g., by welding,metalized spraying, etc.) to the negative electrode extensions/currentcollectors of a second electrode stack, and the positive electrodeextensions/current collectors of a second electrode stack can be fusedto the negative electrode extensions/current collectors of a thirdelectrode stack (separator layers between the electrode stacks notshown). Accordingly, assuming the three electrode stacks are of the sameconstruction, the voltage of the series of electrode stacks is threetimes that of the individual electrode stacks. The unique configurationof the electrode extensions/current collectors of the rechargeableprismatic battery of the present disclosure allows for the fusing of thenegative electrode extensions/current collectors of an electrode stackto the positive electrode extensions/current collectors of anotherelectrode stack. In comparison, conventional prismatic batteryconstruction would not allow for fusing of the negative terminal of abattery to the positive terminal of another battery. Rather, withconventional prismatic battery construction, the negative terminal of abattery would have to be connected to the positive terminal of anotherbattery by way of, for example, a connection plate or fitting. Such aconnection plate or fitting would introduce a current restriction, thuscreating resistance.

Assembly of positive (cathode) electrode plates and negative (anode)electrode plates can comprise stacking a cathode plate atop an anodeplate, which is stacked atop another cathode plate, which is stackedatop another anode plate, etc. In the electrode stack, the alternatingpositive and negative electrode plates can be separated by separatorlayers, which insulate the electrode plates from one another.Alternatively, the flat plate electrodes can be wrapped and sealed in alayer of barrier and separator material to prevent short circuits anddendrite growth, as explained above. Cathode paste or anode paste,respectively, can be applied onto a portion of each of the electrodeplates. With reference to a rechargeable flat plate electrode cellcomprising compressed metal foam, each of the electrode plates can alsohave a portion which can be pressed (i.e., “coined”) to create a thin,flat, high density area (e.g., about 0.15 inch wide), which can serve aselectrode plate extensions.

As illustrated in FIGS. 11 and 12, a rechargeable flat plate electrodecell comprising compressed metal foam exhibits improved performance overcommercially available ZnMn round bobbin consumer cells. In particular,FIG. 11 shows the improvements of a rechargeable flat plate electrodecell comprising compressed metal foam over commercially available ZnMnround bobbin consumer cells (i.e., “Baseline Round Bobbin” and “ImprovedRound Bobbin”) as well as a cell as disclosed in CA 2 389 907 A1 interms of Cell Capacity (expressed as a percentage of initial capacity)Versus Discharge Rate (expressed as a percentage of one hour capacity),while FIG. 12 shows the improvements of a rechargeable flat plateelectrode cell comprising compressed metal foam over commerciallyavailable ZnMn round bobbin consumer cells (i.e., “Baseline RoundBobbin” and “Improved Round Bobbin”) as well as a cell as disclosed inCA 2 389 907 A1 in terms of Cell Capacity (expressed as a percentage ofinitial capacity) versus Cycles/Life (expressed as full charge/dischargeat C/16 and Room Temperature). As can be seen from FIG. 11, arechargeable flat plate electrode cell comprising compressed metal foamhas a capacity of greater than 50% of initial capacity, and inparticular, a capacity of greater than 80% of initial capacity, at adischarge rate of greater than or equal to 50% of one hour capacity. Ascan be seen from FIG. 12, a rechargeable flat plate electrode cellcomprising compressed metal foam has a capacity of greater than or equalto 60% of initial capacity at greater than or equal to 25 cycles at roomtemperature.

With further reference to FIG. 12, the Baseline Round Bobbin was testedfor seven cycles, the Improved Round Bobbin was tested for sixty-fivecycles, and a cell as disclosed in CA 2 389 907 A1 was tested for onehundred cycles. A rechargeable flat plate electrode cell comprisingcompressed metal foam was tested for twenty-five cycles, with predictedresults shown for up to 200 cycles.

Additionally performance characteristics of a rechargeable flat plateelectrode cell comprising compressed metal foam can include capacity ofgreater than 5 Ahr, cycle life exceeding 200 cycles at 80% DOD above 50%initial capacity, power exceeding C/2 rate to 1 V at 50% initialcapacity and 2C rate to 1V at 25% initial capacity, energy densityexceeding 90 Whr/kg, and power density exceeding 180 W/kg. DOD, or depthof discharge, is a measure of how much energy has been withdrawn from abattery, expressed as a percentage of full capacity. C/2 rate refers toa discharge rate of 50% of one hour capacity.

The rechargeable prismatic battery of the present disclosure comprisingcompressed metal foam as well as electrode plate extensions on multiplesides of electrode plate stacks can provide a capacity of greater than50% of initial capacity, and in particular, a capacity of greater than80% of initial capacity, at a discharge rate of greater than or equal to50% of one hour capacity. The rechargeable prismatic battery of thepresent disclosure can provide a capacity of greater than or equal to60% of initial capacity at greater than or equal to 25 cycles at roomtemperature. Additional performance characteristics of the rechargeableprismatic battery of the present disclosure can include capacity ofgreater than 5 Ahr, cycle life exceeding 200 cycles at 80% DOD above 50%initial capacity, power exceeding C/2 rate to 1 V at 50% initialcapacity and 2C rate to 1V at 25% initial capacity, energy densityexceeding 90 Whr/kg, and power density exceeding 180 W/kg. DOD, or depthof discharge, is a measure of how much energy has been withdrawn from abattery, expressed as a percentage of full capacity. C/2 rate refers toa discharge rate of 50% of one hour capacity.

The rechargeable prismatic battery of the present disclosure can also beutilized for other functions including, for example, in a vehicle forstarting a internal combustion engine, as a bulk stationary battery usedto store generated electricity from generators (such as, for example,internal combustion, solar, wind tide, hydro-electric, nuclear,geo-thermal, etc.), as an uninterruptible power supply (UPS) battery (tobe used, for example, in facility/factory back-up, equipment, home,office, etc.), and in a more portable format can be used in power tools,cell phones, laptop computers, and portable electronic devices. Inparticular, the rechargeable prismatic battery of the present disclosureallows for faster charging, making it more convenient for portableapplications, and less gassing, making it safer for personal use. Aportable rechargeable prismatic battery comprising a Mn(O₂) positiveelectrode and a Zn negative electrode would provide advantages such as,for example, having longer charge retention than other rechargeablechemistries commercially available (e.g., NiMH, LiIon, NiCd, Lead Acid,Li Polymer), be lighter and smaller than Ni based batteries, and besafer than Li based batteries.

The following illustrative examples are intended to be non-limiting.

EXAMPLES

With regard to formation of the flat plate anode electrodes, 360 gramsof Zn, 72 grams of ZnO, and 59.88 grams of 2% CMC gel were mixed to forma paste comprising 83.1 weight % zinc active material (i.e., Zn), 16.6weight % solid zinc oxide, and 0.27 weight % polymeric binder. The pastewas applied to one side of copper plated nickel foam and pressed/workedin. The copper was plated on the nickel foam via copper plating 1A for30 minutes. Water was evaporated from the paste, and the dried pastedfoam was pressed to approximately 50% of its original thickness. Furtherdetails of formed flat plate anode electrodes can be found in Table 1,below. With regard to the capacity calculations in Table 1, the capacityof 0.625 g Zn is 512 mAh. An edge section of each of the anode electrodeplates can be pressed to create a thin, flat, high density area, whichcan serve as the anode electrode plate extension used to form a negativecurrent collector.

With regard to formation of the flat plate cathode electrodes, 41.90grams of 2% CMC gel and 100 grams of cathode powder ground down to1/10^(th) of the initial particle size were mixed to form a paste. Thecathode powder comprised electrolytic manganese dioxide, 7.5 weight %graphite/carbon black, 5 weight % polymeric binding agent, 5 weight %barium compound, and 5 weight % hydrogen recombination catalyst, and ispressed to form high density initial particles. The 2% CMC gel providedan additional 1 weight % polymeric binding agent to provide a paste witha total of 6 weight % polymeric binding agent. The paste was applied toone side of nickel foam having a weight basis of 0.255 g/in². Water wasevaporated from the paste, and the dried pasted foam was pressed toapproximately 50% of its original thickness. Further details of formedflat plate cathode electrodes can be found in Table 2, below. An edgesection of each of the cathode electrode plates can be pressed to createa thin, flat, high density area, which can serve as the cathodeelectrode plate extension used to form a positive current collector.

TABLE 1 Anode Design Sized Thickness Paste Sized Sized (Substrate PasteWeight/ Weight Width Length Weight Width Length and Paste) Sized AreaSubstrate (g) (in) (in) (g) (in) (in) (in) (g/in²) A · h/in² A · h/in³ 12.669 2.52 2.37 13.098 2.54 2.50 0.0370 2.063 1.406 37.988 2 2.697 2.522.37 13.258 2.54 2.52 0.0370 2.071 1.411 38.147 3 2.634 2.53 2.38 15.0612.54 2.53 0.0380 2.344 1.597 42.027 4 2.679 2.52 2.35 13.833 2.53 2.470.0370 2.214 1.508 40.767 5 2.631 2.53 2.38 15.144 2.55 2.55 0.03802.329 1.587 41.763 6 2.699 2.50 2.39 14.534 2.53 2.50 0.0370 2.298 1.56642.319 7 2.375 2.54 2.36 15.238 2.56 2.49 0.0380 2.390 1.629 42.867 82.360 2.54 2.36 14.495 2.55 2.48 0.0370 2.292 1.562 42.212 9 2.339 2.522.38 15.492 2.55 2.48 0.0380 2.450 1.669 43.929 10 2.308 2.53 2.3816.602 2.55 2.50 0.0390 2.604 1.775 45.502 11 2.618 2.53 2.37 14.3802.54 2.51 0.0360 2.256 1.537 42.694

TABLE 2 Cathode Design Paste Sized Weight/ Sized Thickness Sized CoatedPaste Sized Sized Coated (Substrate Coated Weight Width Length ThicknessLength Weight Width Length Length and Paste) Area Substrate (g) (in)(in) (in) (in) (g) (in) (in) (in) (in) (g/in²) mAh/in² 1 1.168 2.53 1.810.058 1.54 4.492 2.57 2.02 1.77 0.0250 0.988 216 2 1.170 2.52 1.82 0.0541.56 4.129 2.57 1.97 1.72 0.0235 0.934 205 3 1.141 2.50 1.79 0.050 1.563.555 2.52 1.90 1.66 0.0225 0.850 186 4 1.149 2.49 1.81 0.049 1.57 3.5772.54 1.94 1.69 0.0230 0.833 182 5 1.143 2.49 1.80 0.048 1.58 3.756 2.541.94 1.72 0.0230 0.860 188 6 1.138 2.48 1.80 0.050 1.58 3.815 2.53 1.941.72 0.0235 0.877 192 7 1.139 2.51 1.78 0.052 1.55 4.328 2.56 1.96 1.750.0235 0.966 212 8 1.154 2.50 1.81 0.050 1.56 4.067 2.56 1.96 1.690.0235 0.940 206 9 1.152 2.51 1.80 0.050 1.58 4.041 2.56 1.94 1.740.0230 0.907 199

Many modifications of the exemplary embodiments disclosed herein willreadily occur to those of skill in the art. Accordingly, therechargeable prismatic battery of the present disclosure is to beconstrued as including all structure and methods that fall within thescope of the appended claims.

1. A method of controlling an elevator system, the method comprising:transferring power to an elevator car from a primary power supply to abackup power supply without interruption of power if the primary powersupply fails or is disrupted; and following transfer of power to theelevator car from the primary power supply to the backup power supplyeither: completing pending operations of the elevator car; or moving theelevator car to a predetermined floor based on pending operations of theelevator car.
 2. The method of claim 1, wherein: the primary powersupply comprises AC power; and the backup power supply comprises DCpower.
 3. The method of claim 1, wherein the backup power supply islocated on top of the elevator car.
 4. The method of claim 1, whereinthe backup power supply comprises a rechargeable prismatic batterycomprising: an electrode stack comprised of positive electrode platesand negative electrode plates, wherein: the positive electrode plateseach comprise: manganese; compressed metal foam; and positive electrodeplate extensions that extend beyond a periphery of the electrode stack,and the positive electrode plates are arranged such that the positiveelectrode plate extensions are aligned with one another; and thenegative electrode plates each comprise: zinc; compressed metal foam;and negative electrode plate extensions that extend beyond a peripheryof the electrode stack, and the negative electrode plates are arrangedsuch that the negative electrode plate extensions are aligned with oneanother; positive current collectors formed by fusing the positiveelectrode plate extensions; and negative current collectors formed byfusing the negative electrode plate extensions.
 5. An elevator systemcomprising: an elevator car; a primary power supply; and a backup powersupply attached to the elevator car.
 6. The elevator system of claim 5,wherein the backup power supply is located on top of the elevator car.7. The elevator system of claim 5, wherein: the primary power supplycomprises AC power; and the backup power supply comprises DC power. 8.The elevator system of claim 5, further comprising: solar rechargingcapabilities for the backup power supply.
 9. The elevator system ofclaim 5, wherein the backup power supply comprises a rechargeableprismatic battery comprising: an electrode stack comprised of positiveelectrode plates and negative electrode plates, wherein: the positiveelectrode plates each comprise: manganese; compressed metal foam; andpositive electrode plate extensions that extend beyond a periphery ofthe electrode stack, and the positive electrode plates are arranged suchthat the positive electrode plate extensions are aligned with oneanother; and the negative electrode plates each comprise: zinc;compressed metal foam; and negative electrode plate extensions thatextend beyond a periphery of the electrode stack, and the negativeelectrode plates are arranged such that the negative electrode plateextensions are aligned with one another; positive current collectorsformed by fusing the positive electrode plate extensions; and negativecurrent collectors formed by fusing the negative electrode plateextensions.
 10. A rechargeable prismatic battery comprising: anelectrode stack comprised of positive electrode plates and negativeelectrode plates, wherein: the positive electrode plates each comprise:manganese; compressed metal foam; and positive electrode plateextensions that extend beyond a periphery of the electrode stack, andthe positive electrode plates are arranged such that the positiveelectrode plate extensions are aligned with one another; and thenegative electrode plates each comprise: zinc; compressed metal foam;and negative electrode plate extensions that extend beyond a peripheryof the electrode stack, and the negative electrode plates are arrangedsuch that the negative electrode plate extensions are aligned with oneanother; positive current collectors formed by fusing the positiveelectrode plate extensions; and negative current collectors formed byfusing the negative electrode plate extensions.
 11. The rechargeableprismatic battery of claim 10, wherein the positive current collectorsare connected to a positive terminal.
 12. The rechargeable prismaticbattery of claim 10, wherein the negative current collectors areconnected to a negative terminal.
 13. The rechargeable prismatic batteryof claim 10, wherein the periphery of the electrode stack of positiveelectrode plates comprises a finite number of sides, and further whereinthe positive electrode plate extensions are fused to form positivecurrent collectors at multiple sides of the electrode stack.
 14. Therechargeable prismatic battery of claim 12, wherein the positive currentcollectors are coextensive with the sides of the electrode stack. 15.The rechargeable prismatic battery of claim 10, wherein the periphery ofthe electrode stack of negative electrode plates comprises a finitenumber of sides, and further wherein the negative electrode plateextensions are fused to form negative current collectors at multiplesides of the electrode stack.
 16. The rechargeable prismatic battery ofclaim 15, wherein the positive current collectors are coextensive withthe sides of the electrode stack.
 17. The rechargeable prismatic batteryof claim 10, wherein the periphery of the electrode stack of positiveelectrode plates comprises an even number of sides, and further whereinthe positive electrode plate extensions are fused to form positivecurrent collectors at alternating sides of the electrode stack.
 18. Therechargeable prismatic battery of claim 10, wherein the periphery of theelectrode stack of negative electrode plates comprises an even number ofsides, and further wherein the negative electrode plate extensions arefused to form negative current collectors at alternating sides of theelectrode stack.
 19. The rechargeable prismatic battery of claim 10,wherein all of the positive electrode plates are the same, and all ofthe negative electrode plates are the same.
 20. The rechargeableprismatic battery of claim 10, wherein all of the positive electrodeplate extensions and all of the negative electrode plate extensions arebent at the same angle.
 21. A prismatic battery comprising: an electrodestack comprised of positive electrode plates, negative electrode plates,and separator layers therebetween, wherein: the positive electrodeplates comprise positive electrode plate extensions that extend beyond aperiphery of the electrode stack, and the positive electrode plates arearranged such that the positive electrode plate extensions are alignedwith one another; and the negative electrode plates comprise negativeelectrode plate extensions that extend beyond a periphery of theelectrode stack, and the negative electrode plates are arranged suchthat the negative electrode plate extensions are aligned with oneanother; positive current collectors formed by fusing the positiveelectrode plate extensions; and negative current collectors formed byfusing the negative electrode plate extensions.
 22. The prismaticbattery of claim 21, wherein the positive current collectors areconnected to a positive terminal.
 23. The prismatic battery of claim 21,wherein the negative current collectors are connected to a negativeterminal.
 24. The prismatic battery of claim 21, wherein the peripheryof the electrode stack of positive electrode plates comprises a finitenumber of sides, and further wherein the positive electrode plateextensions are fused to form positive current collectors at multiplesides of the electrode stack.
 25. The prismatic battery of claim 24,wherein the positive current collectors are coextensive with the sidesof the electrode stack.
 26. The prismatic battery of claim 21, whereinthe periphery of the electrode stack of negative electrode platescomprises a finite number of sides, and further wherein the negativeelectrode plate extensions are fused to form negative current collectorsat multiple sides of the electrode stack.
 27. The prismatic battery ofclaim 26, wherein the positive current collectors are coextensive withthe sides of the electrode stack.
 28. The prismatic battery of claim 21,wherein the periphery of the electrode stack of positive electrodeplates comprises an even number of sides, and further wherein thepositive electrode plate extensions are fused to form positive currentcollectors at alternating sides of the electrode stack.
 29. Theprismatic battery of claim 21, wherein the periphery of the electrodestack of negative electrode plates comprises an even number of sides,and further wherein the negative electrode plate extensions are fused toform negative current collectors at alternating sides of the electrodestack.
 30. The prismatic battery of claim 21, wherein all of thepositive electrode plates are the same, and all of the negativeelectrode plates are the same.
 31. The prismatic battery of claim 21,wherein all of the positive electrode plate extensions and all of thenegative electrode plate extensions are bent at the same angle.
 32. Amethod of manufacturing a prismatic battery comprising: stackingpositive electrode plates, negative electrode plates, and separatorlayers therebetween, wherein: the positive electrode plates comprisepositive electrode plate extensions that extend beyond a periphery ofthe electrode stack, and the positive electrode plates are arranged suchthat the positive electrode plate extensions are aligned with oneanother; and the negative electrode plates comprise negative electrodeplate extensions that extend beyond a periphery of the electrode stack,and the negative electrode plates are arranged such that the negativeelectrode plate extensions are aligned with one another; fusing thepositive electrode plate extensions to form positive current collectors;and fusing the negative electrode plate extensions to form negativecurrent collectors.
 33. A method of manufacturing a series of prismaticbatteries comprising: manufacturing multiple prismatic batteries by amethod comprising: stacking positive electrode plates, negativeelectrode plates, and separator layers therebetween, wherein: thepositive electrode plates comprise positive electrode plate extensionsthat extend beyond a periphery of the electrode stack, and the positiveelectrode plates are arranged such that the positive electrode plateextensions are aligned with one another; and the negative electrodeplates comprise negative electrode plate extensions that extend beyond aperiphery of the electrode stack, and the negative electrode plates arearranged such that the negative electrode plate extensions are alignedwith one another and in a direction opposite that in which the positiveelectrode plate extensions are aligned; fusing the positive electrodeplate extensions to form positive current collectors; and fusing thenegative electrode plate extensions to form negative current collectors;and fusing the positive current collectors of one electrode stack to thenegative current collectors of another electrode stack.
 34. A flat plateelectrode cell comprising: positive electrode plates each comprising:manganese; and compressed metal foam; and negative electrode plates eachcomprising: zinc; and compressed metal foam.
 35. The flat plateelectrode cell of claim 34, wherein: the positive electrode plates havealigned positive electrode plate extensions; and the negative electrodeplates have aligned negative electrode plate extensions; and the flatplate electrode cell further comprises: a positive terminal formed fromthe aligned positive electrode plate extensions of the positiveelectrode plates; and a negative terminal formed from the alignednegative electrode plate extensions of the negative electrode plates.